Contrasting Measures of Adherence with Simple Drug Use, Medication Switching, and Therapeutic Duplication

Annals of Pharmacotherapy - Tập 43 Số 1 - Trang 36-44 - 2009
Bradley C. Martin1, Elizabeth Wiley-Exley2, Shirley Richards3, Marisa Elena Domino4, Timothy S. Carey5, Betsy Sleath6,7
1Bradley C Martin PharmD PhD, Professor and Head, Division of Pharmaceutical Evaluation and Policy, University of Arkansas for Medical Sciences, Little Rock, AR
2Elizabeth K Wiley-Exley MPH, Research Assistant, Department of Health Policy and Management, University of North Carolina at Chapel Hill, Chapel Hill, NC
3Shirley Richards BS, Programmer/Analyst, Department of Health Policy and Management, University of North Carolina at Chapel Hill
4Marisa E Domino PhD, Associate Professor, Department of Health Policy and Management, University of North Carolina at Chapel Hill
5Timothy S Carey MD MPH, Director, Cecil G Sheps Center for Health Services Research, University of North Carolina at Chapel Hill
6Betsy Lynn Sleath PhD, Professor, School of Pharmacy, University of North Carolina at Chapel Hill; Cecil G Sheps Center for Health Services Research
7Cecil G Sheps Center for Health Services Research

Tóm tắt

BACKGROUND Multiple measures of adherence have been reported in the research literature and it is difficult to determine which is best, as each is nuanced. Occurrences of medication switching and polypharmacy or therapeutic duplication can substantially complicate adherence calculations when adherence to a therapeutic class is sought. OBJECTIVE To contrast the Proportion of Days Covered (PDC) adherence metric with 2 variants of the Medication Possession Ratio (MPR, truncated MPR). METHODS This study was a retrospective analysis of the North Carolina Medicaid administrative claims data from July 1999 to June 2000. Data for patients with schizophrenia (ICD-9-CM code 295.xx) who were not part of a health maintenance organization, not hospitalized, and not pregnant, taking at least one antipsychotic, were aggregated for each person into person-quarters. The numerator for PDC was defined as the number of days one or more antipsychotics was available and the MPR numerator was defined as the total days’ supply of antipsychotics; both were divided by the total days in each person-quarter. Adherence rates were estimated for subjects who used only one antipsychotic, switched medications, or had therapeutic duplication in the quarter. RESULTS The final sample consisted of 25,200 person-quarters from 7069 individuals. For person-quarters with single antipsychotic use, adherence to antipsychotics as a class was: PDC 0.607, truncated MPR 0.640, and MPR 0.695 (p < 0.001). For person-quarters with switching, the average MPR was 0.690, truncated MPR was 0.624, and PDC was 0.562 (p < 0.001). In the presence of therapeutic duplication, the PDC was 0.669, truncated MPR was 0.774, and MPR was 1.238 (p < 0.001). CONCLUSIONS The PDC provides a more conservative estimate of adherence than the MPR across all types of users; however, the differences between the 2 methods are more substantial for persons switching therapy and prescribed therapeutic duplication, where MPR may overstate true adherence. The PDC should be considered when a measure of adherence to a class of medications is sought, particularly in clinical situations in which multiple medications within a class are often used concurrently.

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Tài liệu tham khảo

10.1111/j.1464-5491.2005.01783.x

10.1093/schbul/sbj075

Haynes R, 1979, Compliance in health care

Sackett D, 1976, Compliance with therapeutic regimens

Schedlbauer A, 2004, Cochrane Database Syst Rev, 18, CD004371

10.1016/S0140-6736(75)92192-3

Sackett D, 1979, The magnitude of compliance and noncompliance

10.1046/j.1365-2710.2001.00363.x

10.1345/aph.1H018

10.1016/S0197-2456(00)00082-9

10.1002/pds.1230

10.1097/00005650-199909000-00002

10.1097/00005650-198808000-00007

Hamilton R, 1992, Am J Hosp Pharm, 49, 1691

10.1016/S0895-7061(97)00056-3

Sclar D, 1991, Clin Ther, 13, 489

10.1016/S0011-393X(05)80254-1

10.1592/phco.26.6.779

Sikka R, 2005, American J Manag Care, 11, 449

10.1097/01.mlr.0000204287.82701.9b

Keene MS, 2005, Am J Manag Care, 11, S362

10.1016/S1098-3015(10)68795-5

10.1097/MLR.0b013e31817924d2

10.18553/jmcp.2006.12.3.239

10.1001/jama.288.4.455

10.1111/j.1524-4733.2006.00139.x

10.1007/s00228-005-0031-9

10.1111/j.1399-5618.2006.00314.x

10.1176/ps.2006.57.8.1094

10.4088/JCP.v65n1013

10.1016/j.schres.2006.02.023

10.1097/01.jcp.0000219917.88810.55

10.1176/ajp.2006.163.4.600

10.1016/S0278-5846(01)00279-2

10.4088/JCP.v67n0317

10.1176/appi.ajp.161.4.692

10.1001/archinte.165.21.2497

10.1016/0895-4356(93)90016-T

10.1002/pds.783

10.1017/S1092852900026675

10.4088/JCP.0207e04

10.1056/NEJMoa051688

10.1176/ps.2008.59.5.507

10.1177/1359786806066070

American Psychiatric Association, 2004, Practice guideline for the treatment of patients with schizophrenia, 2

Lehman A, 2004, Am J Psychiatry, 161, 1

10.1176/ps.49.2.196

10.4088/JCP.v67n1008

10.1097/00005650-200208000-00002

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Annals of Pharmacotherapy

Tập 43 Số 1

36-44

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